Bob, I appreciate the perspective. I know that people love their 485s, and I presume there are good reasons. It really was the best of the line for at least a decade. I'm not sure that I need it for

I don’t fully agree with that recommendation, although it is fine in many circumstances. The impedance of tants stays low at high freqs, while aluminums generally don’t. Tripling the capacitance

1) I understand that I should start with checking the +50V (UNREG) and then 50V (REG)\, next the+ 110V, +15V, and then +5V, -8V and finally -15V. Is this correct?. 4) I understand that TEK used a

My own thoughts - for what they are worth. I have owned two 485's, and they both displayed issues with intermittent attenuators. I would wiggle the knob and try to get a stable trace, but often the

That's a very generous offer and one that we should all keep in mind. I will add, however, that even a new pot may fail in this same way. My guess, and it's only a guess, is that the Tek assembly

Jeff, The 485 is the finest portable Tek made in its day. I paid $350 for mine about 15 years ago and I'd gladly do it again if I had to, but obviously would rather pay less. That 350MHz BW

Barry, If it's that way with several plugins, it might be in hte receiving side of that interface in the 7704A. Stephen

What a fantastic translation. Ramp generator into "catastrophe" generator into "disaster". Google translate without context. I love it!

Hi All, A few years back, (not Tek equipment) I won a beautiful, museum quality cosmetics, Bang & Olufson linear tracking turntable, 1980’s Made in Europe, heavy, IIRC around $225. and the weight

'Disastergenerator' ? I have some of those lying around here !! <grin> Wasn't this setup a replacement for the 160 generators when Tek were getting into Biophysical market.? I understood they rather

Walter, I don't see the fusible element in the 485 schematics, maybe you're thinking of the 7A19, or the 7A24? My wife might not kill me if I got a 485, but I'm in the middle of a reorg of my bench

I have seen a rare lot in

Mark, Yes, I believe the intent is to "highlight" part of the trace; however, mine is highlighting much to bright. I'll have to check those voltage levels in the Z-Axis circuit and see if the

Stephen, I'll have to check that. I think the problem is seen for other time-bases so not sure if it's a problem with the plugin but it could be. Thanks, Barry - N4BUQ

Hi Walter, --- 485 has an active protection circuit that flips input relay to 1M-ohm setting to protect the 50-ohm attenuator. There could be a fusible element as well although I can't see it in the

The next step seems to be to power the board to investigate further. The HV section is basically this (but my unit shows some updates as mentioned previously): https://imgur.com/gtO35ue Can anyone

Jeff, 50 ohm protection on the 485 is a fusible ceramic element in the attenuator chain, a rare and hard to find object. having said that, the 485 scope is very nice, but quite complex (especially in

Barry, Maybe the discussion of Aux Z axis Control and Aux Z Axis Out on pages 3-16 and 3-17 of the 7B53A manual will give a clue. It describes the Z-Axis interface to the mainframe. Since the 7B92A

My brother-in-law worked for a law firm that specialized in maritime law.  He tells a story that happened at the port of Oakland- someone was importing two old MIGs, and they had survived the trip

I have driven forklifts and worked in a workbasket from one. That time, the idiot driver who was assigned to the job kept disappearing. It ran out of propane while I was working near the roof, running